Substrate cleaning method and apparatus

Abstract

A substrate cleaning method for cleaning and removing foreign materials adhered to a surface of a substrate includes heating the substrate to peel off the foreign materials from the surface of the substrate by a thermal stress, removing the foreign materials from the surface of the substrate by a temperature gradient created in a proximity of the surface of the substrate, and collecting the foreign materials removed from the surface of the substrate by a collecting unit facing the substrate.

What is claimed is: 
     
       1. A substrate cleaning method by removing foreign materials adhered to a frontside and a backside surface of a substrate which is mounted on a mounting table by using a collecting unit facing the substrate, the collecting unit including a charging plate, the method comprising:
 heating the substrate to peel off the foreign materials from the frontside surface of the substrate by a thermal stress; 
 charging the charging plate to a first polarity and charging the frontside surface of the substrate to a second polarity that is opposite to the first polarity; 
 removing the foreign materials from the frontside surface of the substrate by a temperature gradient created in a proximity of the frontside surface of the substrate and an electrostatic force exerted on the foreign materials; 
 collecting the foreign materials removed from the frontside surface of the substrate by the collecting unit; 
 lifting the substrate from a surface of the mounting table after removing the foreign materials adhered to the frontside surface of the substrate; and 
 removing foreign materials adhered to the backside surface of the lifted substrate, 
 wherein in said heating and said collecting, a pressure of an atmosphere surrounding the substrate is set to be greater than 1.3×10 2  Pa (1 Torr) and less than or equal to 6.6 kPa (50 Torr), and 
 wherein the pressure of the atmosphere surrounding the substrate during said collecting is set to equal to that during said heating. 
 
     
     
       2. The method of  claim 1 , wherein said heating includes vibrating the frontside surface of the substrate by transmitting ultrasonic waves to the frontside surface of the substrate. 
     
     
       3. The method of  claim 1 , wherein said heating includes irradiating light to the frontside surface of the substrate to vibrate the foreign materials adhered to the frontside surface of the substrate by heat vibration or energy vibration of the light. 
     
     
       4. The method of  claim 3 , wherein the light is irradiated by using a scanning near-field optical microscope (SNOM). 
     
     
       5. The method of  claim 1 , wherein the collecting unit includes a cooling plate and collects the foreign materials by a thermophoretic force due to a temperature gradient created between the substrate and the cooling plate. 
     
     
       6. The method of  claim 1 , further comprising:
 removing foreign materials adhered to the collecting unit after cleaning the frontside surface of the substrate. 
 
     
     
       7. The method of  claim 6 , wherein said removing foreign materials adhered to the collecting unit includes spreading an aerosol to a surface to be cleaned or attaching and detaching an adsorption sheet to and from the surface to be cleaned, thereby peeling off the foreign materials from the surface to be cleaned. 
     
     
       8. The method of  claim 1 , wherein said removing the foreign materials adhered to the backside surface of the substrate includes spreading an aerosol to the backside surface of the substrate, thereby peeling off the foreign materials from the backside surface of the substrate. 
     
     
       9. A substrate cleaning apparatus for removing foreign materials adhered to a frontside and a backside surface of a substrate, the apparatus comprising:
 a mounting table, on which the substrate is mounted; 
 a heating unit configured to heat the substrate mounted on the mounting table to peel off the foreign materials from the frontside surface of the surface by a thermal stress and to remove the foreign materials from the frontside surface of the substrate by a thermophoretic force; 
 a foreign material collecting unit, which is arranged to face the mounting table, the foreign material collecting unit being configured to collect the foreign materials removed from the frontside surface of the substrate, the foreign material collecting unit including a charging plate, the charging plate and the frontside surface of the substrate being charged to opposite polarities; 
 a lifting unit configured to lift the substrate from a surface of the mounting table; and 
 a backside cleaning device configured to remove foreign materials adhered to the backside surface of the substrate lifted by the lifting unit, 
 wherein the substrate cleaning apparatus further comprises a CPU configured to set a pressure of an atmosphere surrounding the substrate to be greater than 1.3×10 2  Pa (1 Torr) and less than or equal to 6.6 kPa (50 Torr) during heating the substrate by using the heating unit and collecting the foreign materials removed from the substrate by using the foreign material collecting unit, and 
 wherein the CPU is further configured to set the pressure of the atmosphere surrounding the substrate during said collecting equal to that during said heating. 
 
     
     
       10. The substrate cleaning apparatus of  claim 9 , wherein the backside cleaning device includes an aerosol cleaning device for spreading an aerosol to the backside surface of the substrate to peel off the foreign materials from the backside surface. 
     
     
       11. The substrate cleaning apparatus of  claim 9 , wherein the backside cleaning device includes an attachment/detachment device for attaching and detaching an adsorption sheet to and from the backside surface of the substrate to peel off the foreign materials from the backside surface. 
     
     
       12. The method of  claim 1 , wherein said removing the foreign materials adhered to the backside surface of the substrate includes attaching and detaching an adsorption sheet to and from the backside surface of the substrate, thereby peeling off the foreign materials from the backside surface of the substrate. 
     
     
       13. The method of  claim 1 , wherein, in said heating and said collecting, the pressure of the atmosphere surrounding the substrate is set to about 1.3 kPa (10 Torr). 
     
     
       14. The substrate cleaning apparatus of  claim 9 , wherein the pressure of the atmosphere surrounding the substrate is set to about 1.3 kPa (10 Torr) during said heating and said collecting.